Top Ten

Real-time voice, video, and data communication over IP is now widely available by way of the ITU-T H.323 standard. Though H.323-based systems are widespread, this standard is surrounded by much hype, misunderstanding, misinformation, and just plain mythology. Some would have you believe that you must be an expert to configure and use H.323 communications, but this just isn't the case. You can start communicating over the IP network in as little as 30 minutes - for free. Here, we'll discuss - and debunk - the top 10 common myths and misunderstandings regarding H.323.

• Myth 1: H.323 is hard to use.
  There are thousands of H.323 users online right now. In fact there are millions of users who have H.323 and don't even realize it. Anyone who's used Microsoft's NetMeeting conferencing utility, bundled with every version of Internet Explorer since 1997, has used H.323. It's also used in the popular AOL and MSN instant messaging services.

  It should be remembered that all communication products start with a small core of dedicated users before spreading into daily use in the wider community. In their day, the phone and the fax were examples of how a snowball can become an avalanche once critical mass has been achieved.

• Myth 2: H.323 directory services are poor.
  For some time, major vendors such as Microsoft have been promoting general directory services such as the Internet Location Service based on the Lightweight Directory Access Protocol (LDAP). While these services are available for almost any application, their usability has had a negative impact on the user experience with H.323 products such as NetMeeting.

  The fundamental problem with this approach is that it assumes users want to look at a "white pages" view of anyone who is online. In reality, most users wish to call from a short list of contacts - we all use the Rolodex much more than the phone book.

  The solution to this problem is the recent adoption of H.323 by instant messaging products such as AOL Instant Messenger and MSN Messenger. These offer a personalized ıbuddy listı and a simple right-click action to make an H.323 connection.

• Myth 3: H.323 is a security risk.
  Any communication solution must reconcile the conflicting requirements of connectivity and security. Cellular phones, for example, are notoriously easy to tap. The H.323 standard provides an excellent basis for implementing effective and secure IP-based communications in a number of ways.

  Because H.323 resides on top of the TCP/IP layer, all IP packet security products work "out of the box." For example, existing firewalls and/or virtual private networks (VPNs) ensure that H.323 traffic passes only between authorized locations within an intranet.

  H.323 also provides excellent security when connecting with others outside of a closed intranet. Firewall and router products from leading vendors such as Cisco and Checkpoint Firewall-1 now support H.323-aware upgrades. These allow H.323 connections to be made selectively without compromising IP network security.

• Myth 4: H.323 software is inferior to hardware.
  H.323 video communications are a testament to the scaled economics of silicon. Because the PC is the largest mass market for processor silicon, the general purpose (Pentium-class) CPU is now capable of outrunning the dedicated video processing chips that were needed to power the first generation of group conferencing systems. While this leaves some video equipment vendors trying to market $15,000 group systems in direct competition with a sub-$1000 PC, the technology itself has revolutionized the possibilities for a huge potential user base.

  The H.323 standard has been implemented in both software and hardware, as exemplified by Micro-soft's NetMeeting and the Polycom ViewStation products, respectively. The software and hardware variants run identical compression and decompression codes - video quality is independent of whether you choose a software or hardware system. The biggest difference is the format of the products: a set-top box appliance versus a desktop PC. Other quality factors are the sophistication of the audio and video devices and the ease of use of an appliance. Users can now access a range of products which meet a full set of requirements and which interoperate effectively using the H.323 standard.

• Myth 5: Streaming video quality beats real-time H.323.
  Streaming video technology has caught on faster than real-time, two-way video. By aping television, video streaming takes advantage of the ıproduce once/playback many" nature of most video communications. Streaming video reduces the processing required for decompression and playback by using a processor-intensive method to compress and prepare video clips in the studio. Streaming compensates for Internet packet loss by buffering video data for between 5 and 30 seconds prior to playback on the client machine.

  Real-time, two-way video is a much more difficult technical problem than streaming. No large video data buffers can be used, as they delay the signal excessively. The compression and decompression both must be executed simultaneously by regular Pentium-class PC systems. Now that this has been achieved technically, the H.323 standard empowers a new wave of Internet video streaming solutions that avoid the interminable buffering delays and allow anyone to produce and edit video clips using a low-cost camera and a PC.

• Myth 6: H.323 is "owned" by Microsoft.
  Microsoft is obviously a strong force in the PC software market and has actively promoted H.323 products - the NetMeeting software client and forthcoming versions of the Microsoft Proxy Server and Exchange 2000, in particular. All the same, by choosing a standards-first approach, Microsoft has helped the H.323 market enormously. By proactively distributing client software, they have shortened the time it takes to reach that critical mass of users, creating a new demand for H.323-enabled services and network equipment. Other vendors actively supporting H.323 include Intel, Cisco, Whitepine, Smith Micro, Lucent, and Siemens. See www.imtc.org for a more complete listing.

• Myth 7: Voice and video over IP serve different needs.
  For many users, the availability of voice over IP (VoIP) holds the promise of free long-distance calls over the Internet. For others, the prospect is for a modern replacement to an ISDN group video-conferencing system within a managed corporate IP intranet. How can these two very different market requirements be reconciled?

  Remember that the Internet has only achieved widespread use over the last three or four years. Already, the amount of data traffic on the Internet has surpassed the amount of voice traffic on the global network. Some very substantial investments are being made to build high-bandwidth, low-latency global networks that will carry voice as simply any other type of IP packet data. Within three years this will be a common form of telephony. Often, voice data will be carried from phone to phone without the users being aware that the carrier has an IP backbone. The H.323 standard is an ideal platform for more valuable and effective communications with the provision of enhancements such as video and data conferencing built in from day one.

• Myth 8: H.323 VoIP is poor quality.
  The H.323 standard defines how terminals (PCs running client software such as NetMeeting or IP telephony handsets that plug straight into the LAN) set up VoIP. The voice quality is determined by several factors: the quality of the audio system, the voice compression techniques used and congestion in the IP network. Provided the network is properly engineered, it is possible to implement high quality audio using the H.323 standard. Where users have uncontested access to 64-kbps or higher bandwidth and the backbone is relatively uncongested, VoIP is as good as toll quality telephony.

  Today, however, many users have only 28.8-kbps access and the public Internet is often congested. The result is lower audio quality than most users expect. But next-generation access technologies such as cable modems and DSL, and next-generation backbone technologies, such as VPN and managed quality of service, are rapidly being deployed worldwide. It will not be long before the benefits of VoIP - low cost and tight integration with data applications - outweigh the pain of switching to a managed quality IP service provider.

• Myth 9: H.323 video is poor quality.
  The H.323 standard uses an improved version of the video compression and decompression technology used in ISDN group conferencing systems: H263+. Video data transmission is well suited to a packet network for two reasons. First, the amount of data being sent is large compared to the packet header information, so there is low overhead. Second, the amount of data varies according to the content of the video - swiftly moving objects generate more data than a ıtalking headı newsreader.

  The net result is that H.323 packet video is actually an improvement over ISDN-based circuit-switched video. Much of the pain of ISDN video has been in buffer delays deliberately inserted to siphon bursty video down a narrow, if constant connection. As with voice quality, this shortcoming is only apparent in a managed IP environment with adequate bandwidth and packet loss performance.

• Myth 10: H.323 video is expensive.
  Sure, H.323 video can be expensive - if you want to use expensive cameras. All that is really needed for a full multimedia H.323 session, however, is a multimedia PC equipped with a low-cost camera such as the Logitech Quickcam VC or the Intel Create and Share products. These items cost less than $100 and connect to the PC via a simple parallel port or USB connection.

Steve Roe is the worldwide marketing director for Ridgeway Systems and Software. He has over 18 years of experience in the global IT industry and holds a degree in Physics from Oxford University. He can be reached at sroe@ridgeway-sys.com. .

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